Inkjet printers eject ink drops from printhead nozzles in response to pressure pulses generated within the printhead by either piezoelectric inkjet ejectors or thermal transducer inkjet ejectors. The pressure pulses propel the ejected ink drops onto a recording medium to form an ink image. In a typical piezoelectric inkjet printer, a controller applies electric pulses, referred to as firing signals, to the piezoelectric inkjet ejectors to produce the pressure pulses, which eject liquid ink drops from the nozzles. The controller may electronically address each inkjet ejector individually to enable a firing signal to be generated and delivered for each inkjet ejector. The firing signal causes a piezoelectric device of the inkjet ejector receiving the firing signal to bend or deform a diaphragm and pressurize a volume of liquid ink in a chamber adjacent the diaphragm. Ink from a reservoir in the printhead refills the inkjet channels as the diaphragm returns to its rest position and produces a negative pressure that pulls ink into the inkjet ejector.
An inkjet printer may print images with numerous types of ink including phase change ink, gel ink, aqueous ink, and the like. Phase change ink, also referred to as solid ink, remains in the solid phase at an ambient temperature, which is the temperature of the air surrounding the printer. Accordingly, before the printhead may eject phase change ink onto the image receiving member, the printer heats the printhead and the solid ink therein to produce liquid ink suitable for ejection. Gel ink remains in a gelatinous state at ambient temperature. Before the printhead ejects gel ink, the printer heats the ink to impart a different viscosity to the ink that is suitable for ejection. Aqueous ink remains in a liquid phase at ambient temperature and, therefore, the printhead may eject aqueous ink without heating the ink.
An inkjet printer configured to print images with phase change ink, gel ink, or other types of heated ink may include an image receiving member in the form of a rotating drum or belt coated with a layer of release agent. The printhead ejects drops of heated liquid ink onto the layer of release agent to form an image. Next, the printer transfers the ink image to a recording medium, such as paper. The printer generally conducts the transfer in a nip formed by the image receiving member and a pressure roller, which is also called a transfix or transfer roller. The printer may include a heater to heat the image receiving member and/or the recording medium prior to entry in the transfixing nip. As the printer transports a recording medium through the nip, the nip transfers the fully formed image from the image receiving member to the recording medium and concurrently fixes the image to the recording medium. This technique of using heat and pressure at a nip to transfer and fix an image to a recording medium passing through the nip is typically known as “transfixing,” a well known term in the art, particularly with phase change ink technology.
The controller of some inkjet printers may cause the printer to enter a power save mode to conserve electrical energy during periods in which the printer refrains from printing images. Specifically, to conserve electrical energy the printer deenergizes the heaters, which heat the image receiving member, the printheads, and other such components. During the power save mode the controller actively monitors the temperature of the heated components and energizes the heaters according to a fixed timing interval to ensure that the temperature of the heated components remains above a predetermined temperature. The aforementioned power save mode reduces the overall energy consumption of the printer; however, in response to increasingly stringent industry standards, further reduction of resource consumption during non-productive periods is desirable.